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TakeFive 08-24-2018 10:08 PM

DIY Fuel Polishing?
I've run my fuel down in my tanks this summer to the point where my (currently empty) jerry can capacity exceeds what's in the tank. I have about 12 gallons in the tank right now. I'm not going to pay for professional polishing service for such a small amount of fuel, but might consider trying to pump out what I have into the jerry cans and filter it back into the tank. I know this will be controversial to those who say I should have the tank professionally scrubbed, etc., but I thought I'd solicit your advice on how to go about doing this with low cost equipment and consumables.

contrarian 08-24-2018 11:01 PM

Re: DIY Fuel Polishing?
Mr. Funnel Fuel Filter. Depending on the layout of your fill tube, the hard part can be getting a tube to the bottom of the tank.
I installed a diverter valve ahead of my primary fuel filter and use a 12 volt pump to empty the tank into jerry cans. Kind of a down and dirty way to do it but it works. You can filter the fuel twice by filtering through the funnel into the jerry cans and then filter again from the jerry cans back to the fuel fill tube. My next project is to put a second diverter valve in the fuel return line and put a dedicated polishing filter between the two lines so that fuel can be polished while sailing in choppy conditions while the engine is not running.

deniseO30 08-24-2018 11:59 PM

Re: DIY Fuel Polishing?
Well if you really want to do it you can! It's nasty smelly and a few other things.

The easy part is making a pump and recirculating setup with really large easily changed High Resistance or high Micron filters.

I would use a a positive displacement pump, it looks like two gears,. it doesn't have to be like a high pressure pressure washer pump, that would be Overkill.
You can recirculate and filter the fuel to your heart's content!

But the job will never really be done if you can't scrub or wash the insides of the tanks to remove all the bio growth and residue.

there are access plates that are easily cut into metal tanks if you don't already have them installed.

You can also make up a nozzle on your high pressure pump so you can use the fuel itself to wash the tank on the inside. Again this does not have to be with a pressure washer type pump. Think garden hose type pressure 50- 80psi

I would check with ww. W grainger. Com all kinds of motors and pumps are available.

Minnewaska 08-25-2018 11:28 AM

Re: DIY Fuel Polishing?
In order to truly polish, you would have to invest multiple times more in filtering media than the $50 in fuel youíre trying to polish. If I didnít have something else I could burn it in, I would pay it forward and donate it to someone in the marina that could use it. Then buy fresh fuel.

As for cleaning the tank yourself, you can do so with solvents, if you have a way to extract them, when your done. Take a peek in and see how bad it is, once youíve pumped out the current contents. I think xylene is often used, but you want a good organic respirator and zero sparking. Iím pretty sure, if you donít get every drop back out, it will readily mix with the diesel, as i think itís the ingredient in many diesel clean additives. This should be confirmed, itís off the top of my head.

hellosailor 08-25-2018 07:09 PM

Re: DIY Fuel Polishing?
It really depends on what's in the tank, and how well you can access it. After one summer of "that *&%#@$ed engine again?!" we decided to just go nuclear on it and make sure that only had to be done once.
Tank access was poor, as usual. So we wound up pulling the batteries, pulling the steering cables, and eventually pulling the tank out through the lazarette. There was less than finger-clearance around it but it could be done.
Then the float valve and access plate came off, and we cleaned out the entire tank as much as it could be accessed. Poured in a big box of rock salt (abrasive when dry) and hand tumbled it, to clean out anything beyond the baffles. a couple of fresh water flushes took out the crud and the remaining salt. Air dryed the tank for 24 hours, put it all together again, and made sure it only got "the very of butter" from then on.
We would have sent the tank out to a radiator shop to be steam cleaned, but they're all rightfully afraid there would be an EPA issue with fuel. If you have a steam gun...that's another option. (All the waste goes in the marina waste oil tank.)

Is DIY practical? Hellyeah. Might take more time than it is worth to you, and wrestling out a tank is not necessarily a solo job. But knowing you're starting on a clean foundation? Priceless. And best done when the tank is near empty.

chef2sail 08-25-2018 07:22 PM

Re: DIY Fuel Polishing?
I agree with the thought that polishing 12 gallons of fuel is a waste of time and energy. Either dispose of it , donate it and then start with entirely fresh good fuel.

However without a cleanup of the interior of the tank, you are really affecting nothing but getting rid of the remaining fuel which MIGHT have card and contaminants. Adding new fuel to an I cleaned tank will still give you issues eventually. If this clean tank is truly important to your peace of mind ( it would be for me) do it right not half way .

mike dryver 08-25-2018 08:55 PM

Re: DIY Fuel Polishing?
So this is what I did on our GulfStar 37 ! The tank had not been tended to for 34 yrs! I pulled the tank fill/fuel line to motor off the tank ! No other way ! Easy ! unbolt !then pumped out tank with a spare PAR water pump, used to pump water tanks ! It had/has a cracked block ! took shaft out of boat, ran fuel line through shaft hole! Pumped fuel through a 2 micron filter into a 55 gal plastic water drum ! let sit for a week, then pumped fuel into a 30 gal plastic water drum thru a 2 micron, and again into tank ! No fuss no mess ! What fumes ! Really !!! Cleaned tank with rags soaked with solvent MEK and or Toluene, on a stick ! Note there were blobs of gasket sealant on the bottom of the tank ! Got them out with solvent ! Note this tank was never looked at for 34 yrs as noted above ! Let's not make a project out of a simple task!!

TakeFive 08-25-2018 10:02 PM

Re: DIY Fuel Polishing?
I have no reason to believe that I have any major problem with my fuel. My filter plugged over a year ago, and Iím not sure when PO changed it, so have no way to know its longevity. I changed both filters then, and I changed the primary last week (proactively, without it plugging). I do know that PO used Biobor and Starbrite detergent additive, which I continue to do in addition to adding OptiLube XPD for its lubricity enhancement of low-sulfur fuel.

Every time I go below 1/2 full on my 25 gal tank, I tell myself, ďIf Iím going to do anything, now is the time.Ē The tank is very difficult to access, and thereís no known reason to remove it.

Iíll probably do nothing aside from running my fuel as low as I can before putting in fresh fuel (and keeping a jerry can onboard in case I cut it too close and run it empty). I was inquiring about pumping out the fuel and filtering it myself outside the boat mainly to extend the life of my very expensive spin-on Racor primary filter.

I actually do get a little bit of polishing when motoring because of the bypass back to the tank. So over time, the fuel does get multiple passes through the existing filters.

Minnewaska 08-26-2018 08:26 AM

Re: DIY Fuel Polishing?

Originally Posted by TakeFive (Post 2051548356)
.....mainly to extend the life of my very expensive spin-on Racor primary filter.....

I believe Racorís advice is to change the filter every 500 hours or annually, whichever comes first. Maybe theyíre just trying to sell more filters, but it stands to reason that chemicals/solvents in our diesel fuel will eventually eat at the filter media. Especially, if more are added by the owner.

Nevertheless, to properly polish fuel outside the boat would also require buying more of these expensive filters, so the economics would not seem to work, even if it did extend the life of those aboard. Just pouring through a gravity filter isnít polishing.

deniseO30 08-26-2018 09:32 AM

Re: DIY Fuel Polishing?
It is a fact, long-term stagnant storage of diesel fuels will have bio growth and condensed water.

Diesel fuel vehicles don't have the problem because they're always moving and the fuel is always agitated to some degree.

Tank cleaning is a business that costs l vehicles ships and storage facilities Millions of dollars,

A sailboat fuel tank is one of the worst because nobody will ever clean them, they sit for months and years while the sludge slowly coats the insides.

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